Ball joints utilised in the steering gear and wheel suspension in cars normally comprise a shell and a ball mounted in this. The function of the shell is as a bearing in the joint and to distribute the lubricant onto the surface of the ball. This is particularly important when the ball lacks other corrosion inhibiting measures. The shell shall also enable preloading of the ball to prevent slip in the connection. In order to mount the ball in a single piece shell, it is necessary to allow the opening at the open end of the shell to be expanded to the same size as the diameter of the ball. Normally this is achieved by splitting this end with 6-8 slots down to the centre of the shell forming lip elements, and there providing a thinning of the shell to enable the lips to be turned outwards, se FIGS. 1 and 2.
The disadvantage of this prior art solution is that all measures mentioned above contribute to reduce the active load bearing area of the shell and thus reduce the load carrying potential at a given diameter. Due to room restrictions it is often necessary to use a ball as small as possible in the joint, which is contradictory of the design of the shells.